KABUL -- Afghanistan's long-delayed parliamentary elections were marred by deadly attacks and descended into chaos with many polling stations hit by technical and organizational problems

Police said a suicide bomber detonated his explosives at a polling station in the capital, Kabul, on October 20, killing at least 10 people, including police officers and voters.

Voting was extended by one day in some constituencies after voters were unable to cast their ballots, with Afghans expressing frustration over polling stations not opening on time, absent election staff, missing election materials, and technical glitches with biometric voter verification devices.

The chaos at the polls came as at least 25 people were killed earlier in the day across the country in attacks on polling stations and security forces.

Multiple blasts struck polling stations in Kabul, leaving at least three dead and over 30 wounded, health officials said. In the central province of Ghor, 11 police officers were killed while three people were killed in the northern province of Kunduz.

Almost 9 million people have registered to vote in the parliamentary election, which are seen as a key test of the government's ability to provide security across the country.

Abdul Badi Sayad, the head of the Independent Election Commission (IEC) said the voting process will continue till October 21 in polling stations where election officers or election material arrived late.

Mohammad Mohaqiq, a deputy to Afghan Chief Executive Officer Abdullah Abdullah, told a local television station that he waited hours to vote and feared frustrated voters would abandon the polling stations without marking their ballots.

Sayad said technical glitches had occurred, although he did not say if polling would be extended.

'More than 3,000 men and around 2,000 women are standing on the streets outside this polling station," a resident of the western city of Herat told RFE/RL. "They don't know what to do. The election officials say the voter registration lists haven't arrived."

Election posters in Kabul

Khaled Haq Parast, a Kabul police official, said two police officers were wounded when they tried to defuse an improvised explosive devise found near a polling station in Kabul. He said two civilians were also injured.

Jan Agha, another police official in the Afghan capital, said a 'sticky bomb' -- a type of improvised grenade -- placed underneath the vehicle of an intelligence official exploded in Kabul but no one was hurt.

Officials said two people were wounded in the western province of Farah after a mortar landed in a residential area. In the eastern province of Kunar, gunmen fired on polling stations, leaving two injured.

Seven people were wounded in the eastern province of Nangarhar.

Interior Ministry spokesman Nasrat Rahimi said several 'plots' in Kabul and elsewhere had been 'neutralized.'

'Several plots in the [provinces of] Kabul, Takhar, Badakhshan, and Jowzjan have been exposed and neutralized,' he said.

The Interior Ministry announced that an additional 20,000 security personnel had been deployed to protect voters and polling stations, bringing the total number to around 70,000.

Despite the risks, President Ashraf Ghani urged 'every Afghan, young and old, women and men' to exercise their right to vote, after casting his ballot in Kabul.

Photos posted on social media showed scores of men and women holding their identification documents lining up outside polling stations across the country amid a heavy security presence.

Ahmad Hanayesh, a RFE/RL correspondent in the northern province of Parwan, said despite worries over low turnout many people had turned up to cast their ballots in the face of security concerns and technical problems at polling stations.

"The queues are long and they show people's interest in the election,' he said.

Shamila Jawed, a RFE/RL correspondent in Kabul, said there were "extreme irregularities in the voting process" at a polling station she visited in the capital.

Originally scheduled for 2015, the parliamentary vote was delayed for three years amid disputes over electoral reforms and because of the instability following NATO's handover of security responsibilities to Afghan forces at the end of 2014.

In a fresh warning issued on October 20, the Taliban urged voters to boycott the 'sham and theatrical process to protect their lives.'

Election campaign workers prepare biometric devices in Kabul.

The killing of the powerful police chief of the southern province of Kandahar on October 18 has eroded confidence in the ability of the government to conduct the vote safely and transparently despite ongoing fighting between government forces and militants in at least 20 of Afghanistan's 34 provinces.

Voting in Kandahar has been delayed by a week following the attack, which killed three people, including the provincial intelligence chief. It also left the provincial governor in critical condition.

Candidates, campaign rallies, and senior security officials have been targeted in deadly attacks by Taliban and Islamic State (IS) extremists -- including suicide attacks, motorcycle bombings, and drive-by shootings.

During the three-week campaign period, two candidates and 34 civilians were killed in militant attacks.

Eight other candidates were killed by militants during the run-up to campaigning, and the fate of two abducted candidates remains unknown.

Elections will not be held on October 20 in 10 Afghan districts in different parts of the country that are under Taliban control.

They include five districts in the Taliban stronghold of Helmand Province, two in the northeastern province of Badakhshan, one in the southern province of Zabul, and districts in the northern provinces of Baghlan and Sar-e Pul.

Voting also has been postponed indefinitely in Ghazni Province amid a dispute over how to map out voting precincts to achieve more balanced ethnic representation.

Voting for district councils across the country also was supposed to take place on October 20, but has been postponed amid threats by the Taliban to attack candidates and security forces.

Altogether, there are more than 2,500 candidates contesting 249 seats in Afghanistan's lower house of parliament, known as the Wolesi Jirga. Of those candidates, 417 are women.

Hundreds of those running are young, first-time candidates who include reporters, entrepreneurs, and educators.

But no major opposition party is poised to win enough seats to contest the national unity government headed by Ghani and Abdullah.

Most candidates for parliament are running as independents.

With reporting by AP, Reuters, and AFP RFE/RL's Radio Free Afghanistan

RFE/RL's Radio Azadi is the leading media outlet in Afghanistan today, reaching more than 60 percent of the Afghan population across the country with its radio and Internet programs.